Automatic locking retractors are relatively well known in the art and the U.S. Pat. No. 3,174,704 to Replogle; U.S. Pat. No. 3,412,952 to Wohlert; and U.S. Pat. No. 3,667,698 to Fisher are characteristic of such devices in commercial usage. All involve a reel or drum which is a receptacle for safety webbing or harness. The drum is biased to rewind the harness by a retractor spring motor which winds the webbing on the drum. The drum includes ratchet means movable with the drum and providing a one-way lock against withdrawal of webbing when a pawl is engaged therewith. The pawl is pivotal on the frame which supports the drum and is spring biased toward closure against the teeth of the ratchet. In Replogle the pawl is pivotal on a shaft which includes a webbing feeler and a cripple link, the latter selectively engageable or disengageable from the drum shaft on recock depending upon the slight retraction of the webbing after withdrawal beyond the contact of the webbing feeler with the webbing. Retraction was noisy until the retracting motion built up sufficient webbing on the drum to lift the pawl away from engagement with the ratchet. In Wohlert and in Fisher a face clutch structure selectively moves a blocking cam plate to free a spring biased pawl so that engagement with the ratchet is possible. The blocking cam plate during initial withdrawal of webbing prevents lock-up, but on a slight retraction of the webbing, and corresponding motion of the cam plate, the blocking cam plate is released from its blocking of the pawl and on any further withdrawal, the pawl engages the ratchet. In Wohlert, the initial free-pull is dependent upon a webbing feeler or sensor which holds the pawl away from ratchet engagement and allows the cam plate to achieve its blocking position until otherwise influenced by retraction after withdrawal beyond the sensor contact limit. In Fisher the sensing for free-pull is determined by a gear driven element which is essentially a rotation counter and depending on the desired number of rotations, it holds the pawl out of all possible locking action until the desired withdrawal has occurred. Concurrently, a face clutch operated blocking cam plate is moved into blocking relation to be released on slight retraction. Then the cam is freed from its blocking relation and further withdrawal is prevented because the pawl can and does contact the ratchet and prevent the drum from withdrawal. On further retraction, after the slight retraction, the cam blocking plate locates in a secondary blocking of the pawl preventing noise by preventing contact of pawl to ratchet during rewind.
As will be seen, the present invention contemplates the use of an interposer acted upon by selected drum motion to provide an interference with a spring biased pawl thereby avoiding the need or desire for a cripple link construction and avoiding the necessity of a face clutch construction driving from the drum. The present invention is amenable to a rotation counting system but greatly simplifies the linkages required and at substantial reduction of weight and parts.
Accordingly, the principal object is to provide a new structure for actuating the pawl lock in automatic locking retractors.
Another object is to provide a new and inventive means for blocking the pawl of a safety belt retractor which is acted upon by a ring and most particularly the outer surface of the ring and where the ring is moved in selected (as by geared) proportion to the movement of the retractor drum.
Another object is to provide an interposer blocker to assure initial quiet free-pull and quiet retraction in the inertial retractor of the copending application Ser. No. 258,576 filed on June 1, 1972 now U.S. Pat. No. 3,865,320.
Other objects including quiet actuation on retraction and withdrawal together with a reel amenable to easy electrical interlock integration and with savings in parts and complexity will be increasingly appreciated as the description proceeds.